gms | German Medical Science

Objective: In normal brain, the potent vasoconstrictive Neuropeptide Y (NPY) is abundantly expressed in the hypothalamus, forebrain, hippocampus and brainstem. NPY is stored in perivascular nerve fibres of the cerebral arteries, regulating cerebral vascular diameter and blood flow. Its role in the pathogenesis of subarachnoid hemorrhage (SAH) – related vasospasm is unclear. We prospectively analyzed and compared the release of NPY in the cerebrospinal fluid (CSF) of 66 patients with SAH to a control group. Additionally, we correlated the levels of NPY to vasospasm and consecutive stroke.

Method: 66 consecutive patients (40 female, 26 male; mean age 53.1 years) with aneurismal SAH were included. In the SAH group, CSF was drawn daily from day 1 to day 10 after onset of the SAH. The CSF of 29 patients undergoing spinal anesthesia for orthopedic surgery served as control samples. Determination of NPY levels was obtained in duplicate CSF samples using a competitive enzyme immunoassay (EIA).

Results: Levels of NPY were significantly higher in the SAH group compared to the control group (p<0.001). Patients with vasospasm revealed significantly higher NPY levels compared to patients without vasospasm during the entire observation period. The NPY levels of the non-vasospasm group dissipated over time whereas the vasospasm group displayed a continuous increase of the values. NPY levels from day 4-10 were significantly higher in patients with vasospasm related stroke compared to patients with no stroke. Using 0.3 ng/ml as the cutoff value, NPY levels on day 3 predict the occurrence of vasospasm with a sensitivity and specificity of 82% and 72%, respectively. High NPY levels starting from day 4 significantly correlated with poor GOS rating at follow-up (p<0.05).

Conclusions: Our data indicate that NPY is involved in the pathogenesis of SAH related vasospasm. Further analyses of the biological role and its use as a prognostic biomarker are underway.